Steel dust and mud pyrogenic process dezincification composite agent, preparation method and application thereof

Abstract

The invention discloses a composite agent for pyrogenic dezincification of steel dust and mud and a preparation method and application thereof, and belongs to the technical field of resourceful treatment of steel dust and mud. The composite agent is prepared from the following raw materials: reduced carbon, humic acid, molasses, a fluxing agent, a pore forming agent and a stabilizer; the reducing carbon is at least one of lignite and coke powder; the stabilizer is forsterite or magnesite. The preparation method comprises the following steps: S1, pretreating reduced carbon; s2, sequentially dispersing molasses and humic acid in water, then adding the reduced carbon pretreated in the step S1, a fluxing agent, a stabilizer and a pore forming agent, and mixing to form slurry; s3, granulating the slurry to obtain particles; and S4, carrying out pore forming on the particles to obtain the steel dust and mud pyrogenic process dezincification composite reagent. The steel dust and mud pyrogenic process dezincification composite agent is high in strength, large in specific surface area, not prone to agglomeration in the pyrogenic process sintering process and higher in zinc reduction efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel dust and sludge resource treatment, and particularly relates to a steel dust and sludge fire-based zinc removal composite agent, a preparation method thereof and application thereof. BACKGROUND

[0002] With the rapid development of the steel industry, a large amount of zinc-containing dust and sludge is generated in the steel smelting process, and the dust and sludge is rich in iron and zinc, in which zinc mainly exists in the form of zinc oxide and zinc ferrite. How to efficiently separate and recover iron and zinc in the dust and sludge has become an important issue in the resourceization of solid waste in the steel industry.

[0003] At present, the treatment methods for steel dust and sludge mainly include a fire-based process (rotary kiln, rotary hearth furnace, sintering machine) and a wet process (acid leaching, alkali leaching). Among them, the fire-based process has become the mainstream technology due to its large treatment capacity and strong adaptability. However, the existing fire-based process still has the following problems: (1) incomplete zinc removal: zinc ferrite is difficult to decompose under conventional fire-based conditions, resulting in residual zinc in the slag and affecting the quality of iron products; (2) traditional carbon thermal reduction requires high temperature, consumes a large amount of fuel, and easily leads to sintering of iron particles, reducing the metallization rate; (3) zinc vapor is easy to form fine particles after condensation, and if the tail gas is not properly treated, it will cause heavy metal pollution. SUMMARY

[0004] The application provides a steel dust and sludge fire-based zinc removal composite agent, a preparation method thereof and application thereof to overcome the above technical problems. The steel dust and sludge fire-based zinc removal composite agent has high strength and large specific surface area, is not easy to agglomerate during fire-based sintering, and has higher zinc reduction efficiency.

[0005] The application solves the above technical problems through the following technical solutions.

[0006] A steel dust and sludge fire-based zinc removal composite agent, comprising the following preparation raw materials in parts by mass: 40-70 parts of reducing carbon, 10-30 parts of humic acid, 7-20 parts of molasses, 10-20 parts of fluxing agent, 3-12 parts of pore-forming agent and 5-15 parts of stabilizer. Preferably, the steel dust and sludge fire-based zinc removal composite agent comprises the following preparation raw materials in parts by mass: 45-65 parts of reducing carbon, 15-25 parts of humic acid, 12-18 parts of molasses, 10-15 parts of fluxing agent, 5-8 parts of pore-forming agent and 8-13 parts of stabilizer. In the application, the humic acid releases active free radicals upon pyrolysis, preferentially attacks the zinc-oxygen bond in zinc ferrite, and decomposes the zinc ferrite. The carbon monoxide generated by the reducing carbon provides a continuous reducing atmosphere.

[0007] The stabilizer can form a high-melting-point phase at high temperature, which wraps the residual zinc oxide and avoids its recombination with ferrous oxide.

[0008] The molasses plays a role of adhesion, the binder is used for enhancing the plasticity of the pellet, improving the strength of the medicament, avoiding the local densification caused by the crushing after the breaking or sintering, and avoiding the blocking of the pores after the sintering.

[0009] The fluxing agent helps to form a low-viscosity liquid phase, improve the flowability of the slag phase, wet the zinc ferrite particles and destroy the crystal structure thereof. The stabilizer can avoid the secondary oxidation of zinc, and the magnesium-containing stabilizer can make the magnesium ions replace the zinc ferrite to form more stable magnesium ferrite.

[0010] According to some embodiments of the present application, the steel and iron dust slurry is derived from at least one of sintering dust slurry, blast furnace dust slurry, steelmaking dust slurry, converter dust slurry, electric furnace dust slurry and rolling steel oxide skin.

[0011] According to some embodiments of the present application, the steel and iron dust slurry contains zinc content of 2-15%, preferably 2.5-8%.

[0012] According to some embodiments of the present application, the steel and iron dust slurry contains iron content of 25-60%, preferably 40-55%.

[0013] According to some embodiments of the present application, the reducing carbon is at least one of lignite and coke powder; preferably, the mass ratio of lignite to coke powder in the reducing carbon is 10:0-5, for example, 10:2-3.

[0014] According to some embodiments of the present application, the stabilizer is forsterite or magnesite.

[0015] According to some embodiments of the present application, the fluxing agent is at least one of calcium oxide, magnesium oxide, borax and dolomite; preferably, the fluxing agent is calcium oxide or magnesium oxide.

[0016] According to some embodiments of the present application, the pore-forming agent is ammonium bicarbonate or ammonium oxalate; preferably, the pore-forming agent is ammonium bicarbonate.

[0017] According to some embodiments of the present application, the specific surface area of the steel and iron dust slurry fire method zinc removal composite medicament is 230-280 m 2 / g, preferably 240-275 m 2 / g.

[0018] According to some embodiments of the present application, the average compressive strength of the steel and iron dust slurry fire method zinc removal composite medicament is 10-15 N / pellet, preferably 12-15 N / pellet.

[0019] The present application also discloses a preparation method of a steel and iron dust slurry fire method zinc removal composite medicament, comprising the following steps: S1. The reducing carbon needs to be pretreated, the pretreatment step is to crush, screen and then acid soak the reducing carbon, and filter and dry for standby. S2. The reducing carbon is mixed with the fluxing agent, the stabilizer and the pore-forming agent to obtain a mixture; S2. Disperse molasses and humic acid in water in sequence, then add the reduced carbon, flux, stabilizer and pore-forming agent pretreated in S1 and mix to form a slurry; S3. Granulate the slurry to obtain granules; S4. After creating pores in the particles, a composite agent for the pyrometallurgical dezincification of steel dust and sludge is obtained.

[0020] In S1, the mesh size of the sieve used for screening is 500-800 mesh; In step S1, the acid leaching involves soaking the reduced carbon in 1-2 mol / L hydrochloric acid for 2-4 hours to reduce the ash content and increase the specific surface area. After acid leaching, the carbon is filtered dry. The reduced carbon after acid leaching has lower ash content and a larger specific surface area, which is beneficial for the subsequent preparation of reagents.

[0021] In S2, the solid content of the slurry is 50-70%; In S3, the granulation is carried out by extrusion granulation, and the granulation pressure is 5~10MPa.

[0022] In S3, the output particle size of the granulation is 3~10mm.

[0023] In S4, the hole-making step is to preheat at 70~85℃ for 20~30 minutes, then introduce saturated water vapor for 15~25 minutes, cool, and then dry until the water content is <5%.

[0024] An application process for a composite agent for pyrometallurgical dezincification of steel dust includes the following steps: adding the composite agent for pyrometallurgical dezincification of steel dust to the steel dust and then sintering. The mass ratio of the steel dust and sludge to the pyrometallurgical dezincification composite agent is 100:10~30.

[0025] According to some embodiments of the present invention, the application process employs a rotary kiln, and the kiln section control is divided into a drying section, a preheating section, a high-temperature section, and a cooling section. The drying section is heated at a temperature of 200~400℃ for 15~20 minutes; The preheating section is heated at a temperature of 400~800℃ for 25~30 minutes; The high-temperature section is heated at 800~1100℃ for 20~30 minutes; The cooling section cools the temperature to 800~850℃.

[0026] According to some embodiments of the present invention, the zinc removal efficiency of the composite agent for pyrometallurgical dezincification of steel dust is ≥97%, preferably 97.5~99%.

[0027] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0028] Compared with the prior art, the beneficial effects of the present invention are: 1. The main raw material component of the composite agent for pyrometallurgical zinc removal from steel dust in this invention is reducing carbon, followed by humic acid; the pyrolysis of reducing carbon generates carbon monoxide, which can be used to reduce zinc oxide and zinc ferrite, and provides the heat required for the reaction; the pyrolysis of humic acid generates active free radicals that promote the decomposition of zinc ferrite.

[0029] 2. The preparation method of the composite agent for pyrometallurgical dezincification of steel dust in this invention is simple and requires no complex equipment. The final granulation strength is high, meeting the mechanical conveying requirements of rotary kilns. Furthermore, the formulation is flexible, allowing adjustment of the proportions of reducing carbon, flux, and stabilizers according to the composition of the dust. Attached Figure Description

[0030] Figure 1 This is a SEM image of the composite agent for pyrometallurgical dezincification of steel dust and sludge from Example 1.

[0031] Figure 2 The image shows the SEM image of the composite agent for pyrometallurgical dezincification of steel dust in Comparative Example 4. Detailed Implementation

[0032] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0034] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is understood that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this invention, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein; "0-5" is merely a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer greater than or equal to 2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0036] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0037] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0038] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0039] Unless otherwise specified, the term "or" is inclusive in this invention. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0040] The steel dust in the following examples is derived from steelmaking dust and contains the following components by mass fraction: 2.99% zinc and 52.33% iron.

[0041] Example 1 1. The composite agent for pyrometallurgical dezincification of steel dust in this embodiment comprises the following raw materials in parts by weight: 55 parts lignite, 20.2 parts humic acid, 15.4 parts molasses, 15.3 parts calcium oxide, 7.8 parts ammonium bicarbonate and 10.7 parts magnesium olivine; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 268 m². 2 / g, with an average compressive strength of 14.7 N / piece.

[0042] 2. The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust in this embodiment is as follows: S1. After crushing the reduced carbon, sieve it twice through a 600-mesh sieve, soak it in 1.5 mol / L hydrochloric acid solution for 3 hours, filter it dry and set it aside for later use. S2. Molasses and humic acid are dispersed in water in sequence, and then the reduced carbon, flux, stabilizer and pore-forming agent pretreated in S1 are added and mixed to form a slurry with a solid content of 58%. S3. Granulate the slurry to obtain 4-7mm particle size, and air dry naturally to obtain granules; S4. Preheat the granules at 80℃ for 20 minutes, then pass saturated steam through them for 20 minutes, cool them, and then dry them with hot air until the water content is 2%.

[0043] The SEM image of the composite agent for pyrometallurgical zinc removal from steel dust prepared in this embodiment is shown below. Figure 1 The agent has many pores on its surface and a large specific surface area.

[0044] Example 2 1. The composite agent for pyrometallurgical dezincification of steel dust in this embodiment includes the following raw materials in parts by weight: 51 parts reducing carbon (the mass ratio of lignite to coke powder is 10:2.1), 18.1 parts humic acid, 17.5 parts molasses, 10.9 parts magnesium oxide, 5.3 parts ammonium bicarbonate and 8.6 parts magnesite; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 257 m². 2 / g, with an average compressive strength of 13.2 N / piece.

[0045] 2. The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust in this embodiment is as follows: S1. After crushing the reduced carbon, sieve it twice through a 600-mesh sieve, soak it in a 2 mol / L hydrochloric acid solution for 3 hours, filter it dry and set it aside for later use. S2. Molasses and humic acid are dispersed in water in sequence, and then the reduced carbon, flux, stabilizer and pore-forming agent pretreated in S1 are added and mixed to form a slurry with a solid content of 60%. S3. Granulate the slurry to obtain 4-7mm particle size, and air dry naturally to obtain granules; S4. Preheat the granules at 75℃ for 15 minutes, then pass saturated steam through them for 20 minutes, cool them, and then dry them until the water content is 2%.

[0046] Example 3 1. The composite agent for pyrometallurgical dezincification of steel dust in this embodiment includes the following raw materials in parts by weight: 50 parts lignite, 22.2 parts humic acid, 12.5 parts molasses, 15.8 parts calcium oxide, 8 parts ammonium bicarbonate and 9.7 parts magnesium olivine; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 262 m². 2 / g, with an average compressive strength of 12.8 N / particle.

[0047] 2. The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust in this embodiment is as follows: S1. After crushing the reduced carbon, sieve it twice through a 600-mesh sieve, soak it in 1.5 mol / L hydrochloric acid solution for 4 hours, filter it dry and set it aside for later use. S2. Molasses and humic acid are dispersed in water in sequence, and then the reduced carbon, flux, stabilizer and pore-forming agent pretreated in S1 are added and mixed to form a slurry with a solid content of 60%. S3. Granulate the slurry to obtain 4-7mm particle size, and air dry naturally to obtain granules; S4. Preheat the granules at 85℃ for 25 minutes, then pass saturated steam through them for 25 minutes, cool them, and then dry them until the water content is 2%.

[0048] Example 4 1. The composite agent for pyrometallurgical dezincification of steel dust in this embodiment includes the following raw materials in parts by weight: 50 parts reducing carbon (the mass ratio of lignite to coke powder is 10:2.8), 17.1 parts humic acid, 13.4 parts molasses, 13.3 parts calcium oxide, 5.9 parts ammonium oxalate and 5.8 parts magnesium olivine; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 255 m². 2 / g, with an average compressive strength of 13.5N / particle.

[0049] 2. The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust in this embodiment is as follows: S1. After crushing the reduced carbon, sieve it twice through a 600-mesh sieve, soak it in a 2 mol / L hydrochloric acid solution for 3 hours, filter it dry and set it aside for later use. S2. Molasses and humic acid are dispersed in water in sequence, and then the reduced carbon, flux, stabilizer and pore-forming agent pretreated in S1 are added and mixed to form a slurry with a solid content of 60%. S3. Granulate the slurry to obtain 4-7mm particle size, and air dry naturally to obtain granules; S4. Preheat the granules at 70℃ for 25 minutes, then pass saturated steam through them for 20 minutes, cool them, and then dry them until the water content is 2%.

[0050] Example 5 1. The composite agent for pyrometallurgical dezincification of steel dust in this embodiment includes the following raw materials in parts by weight: 49 parts reducing carbon (the mass ratio of lignite to coke powder is 10:3), 18.7 parts humic acid, 14.6 parts molasses, 14.1 parts calcium oxide, 7.2 parts ammonium oxalate and 9.5 parts magnesite; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 251 m². 2 / g, with an average compressive strength of 12.5 N / piece.

[0051] 2. The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust in this embodiment is as follows: S1. After crushing the reduced carbon, sieve it twice through a 600-mesh sieve, soak it in a 2 mol / L hydrochloric acid solution for 3 hours, filter it dry and set it aside for later use. S2. Molasses and humic acid are dispersed in water in sequence, and then the reduced carbon, flux, stabilizer and pore-forming agent pretreated in S1 are added and mixed to form a slurry with a solid content of 60%. S3. Granulate the slurry to obtain 4-7mm particle size, and air dry naturally to obtain granules; S4. Granulate the particles in saturated steam for 10 minutes, cool, and then dry until the water content is 2%.

[0052] Example 6 1. The composite agent for pyrometallurgical dezincification of steel dust in this embodiment includes the following raw materials in parts by weight: 50.2 parts reducing carbon (the mass ratio of lignite to coke powder is 10:3), 18.4 parts humic acid, 16.9 parts molasses, 11.7 parts calcium oxide, 7.8 parts ammonium bicarbonate and 9.6 parts magnesium olivine; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 248 m². 2 / g, with an average compressive strength of 12.2 N / piece.

[0053] 2. The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust in this embodiment is as follows: S1. Crush the reduced carbon and set it aside; S2. Molasses and humic acid are dispersed in water in sequence, and then reducing carbon, flux, stabilizer and pore-forming agent are added and mixed to form a slurry with a solid content of 60%. S3. Granulate the slurry to obtain 4-7mm particle size, and air dry naturally to obtain granules; S4. Preheat the granules at 75℃ for 25 minutes, then pass saturated steam through them for 20 minutes, cool them, and then dry them until the water content is 2%.

[0054] Comparative Example 1 The difference between this comparative example and the embodiment is: The comparative example of the composite agent for pyrometallurgical dezincification of steel dust includes the following raw materials in parts by weight: 55 parts lignite, 15 parts molasses, 12.7 parts calcium oxide, 6.3 parts ammonium bicarbonate and 9.4 parts magnesium olivine; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 235 m². 2 / g, with an average compressive strength of 11.5 N / particle.

[0055] The other raw materials, steps and parameters are the same as in Example 1.

[0056] Comparative Example 2 The difference between this comparative example and the embodiment is: The comparative example of the composite agent for pyrometallurgical dezincification of steel dust includes the following raw materials in parts by weight: 46.8 parts lignite, 18.7 parts humic acid, 15.1 parts molasses, 14.2 parts calcium oxide and 11.3 parts magnesium olivine; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 220 m². 2 / g, with an average compressive strength of 10.8 N / piece.

[0057] The other raw materials, steps and parameters are the same as in Example 1.

[0058] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: The comparative example of the composite agent for pyrometallurgical dezincification of steel dust includes the following raw materials in parts by weight: 48.9 parts lignite, 16.8 parts humic acid, 16.0 parts molasses, 13.4 parts calcium oxide and 6.2 parts ammonium bicarbonate; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 215 m². 2 / g, with an average compressive strength of 10.2N / particle.

[0059] The other raw materials, steps and parameters are the same as in Example 1.

[0060] Comparative Example 4 The difference between this comparative example and Example 1 is as follows: The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust in this comparative example is as follows: S1. After crushing the reduced carbon, sieve it twice through a 600-mesh sieve, soak it in a 2 mol / L hydrochloric acid solution for 2 hours, filter it dry and set it aside for later use. S2. Molasses and humic acid are dispersed in water in sequence, and then the reduced carbon, flux, stabilizer and pore-forming agent pretreated in S1 are added and mixed to form a slurry with a solid content of 60%. S3. Granulate the slurry to obtain particles with a discharge particle size of 5~8mm, air dry naturally to obtain granules, and dry until the water content is 2%; The specific surface area of ​​the composite agent for pyrometallurgical zinc removal from steel dust is 197 m². 2 / g, with an average compressive strength of 9.8 N / particle.

[0061] The other raw materials, steps and parameters are the same as in Example 1.

[0062] The SEM image of the composite agent for pyrometallurgical zinc removal from steel dust in this comparative example is shown below. Figure 2 .

[0063] Application examples The steps for applying the composite agent for pyrometallurgical dezincification of steel dust prepared in the above embodiments and comparative examples to practical applications are as follows: The steel dust and sludge and the pyrometallurgical dezincification composite agent are mixed at a mass ratio of 100:20 and added to the rotary kiln. The kiln is divided into a drying section, a preheating section, a high-temperature section, and a cooling section. The drying section is heated at 300℃ for 15 minutes, the preheating section is heated at 650℃ for 25 minutes, the high-temperature section is heated at 1000℃ for 30 minutes, and the cooling section is cooled to 850℃ after 22 minutes.

[0064] The zinc content in the treated steel dust was tested according to the national standard GB / T 38233-2019, and the zinc removal rate was calculated. The results are shown in Table 1.

[0065]

[0066] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this invention. It should be understood that the above descriptions are merely specific embodiments of this invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A steel dust sludge fire method dezincification composite reagent, characterized in that, The preparation raw materials include the following quality parts: 40-70 parts of reducing carbon, 10-30 parts of humic acid, 7-20 parts of molasses, 10-20 parts of fluxing agent, 3-12 parts of pore forming agent and 5-15 parts of stabilizer; Preferably, the steel dust and sludge fire method zinc removal composite agent includes the following quality parts of preparation raw materials: 45-65 parts of reducing carbon, 15-25 parts of humic acid, 12-18 parts of molasses, 10-15 parts of fluxing agent, 5-8 parts of pore forming agent and 8-13 parts of stabilizer.

2. The steel dust sludge fire method dezincification composite reagent according to claim 1, characterized in that, At least one of the following conditions a-c is met: a. The steel dust and sludge is derived from at least one of sintering dust and sludge, blast furnace dust and sludge, steelmaking dust and sludge, converter dust and sludge, electric furnace dust and sludge and rolling steel oxide skin; b. The zinc content in the steel dust and sludge is 2-15wt%, preferably 2.5-8%; c. The iron content in the steel dust and sludge is 25-60wt%, preferably 40-55%.

3. The steel dust sludge fire method dezincification composite reagent according to claim 1, characterized in that, At least one of the following conditions a-d is met: a. The reducing carbon is at least one of lignite and coke powder; Preferably, the mass ratio of lignite to coke powder in the reducing carbon is 10:0-5, for example 10:2-3; b. The stabilizer is forsterite or magnesite; c. The fluxing agent is at least one of calcium oxide, magnesium oxide, borax and dolomite; preferably, the fluxing agent is calcium oxide or magnesium oxide; d. The pore forming agent is ammonium bicarbonate or ammonium oxalate; preferably, the pore forming agent is ammonium bicarbonate.

4. The steel dust sludge fire method dezincification composite reagent according to claim 1, characterized in that, At least one of the following conditions a-b is met: a. The specific surface area of the steel dust and sludge fire method dezincification composite agent is 230~280 m 2 / g, preferably 240~275 m 2 / g; b. The average compressive strength of the steel dust and sludge fire method zinc removal composite agent is 10-15 N / pellet, preferably 12-15 N / pellet.

5. A method for preparing a composite reagent for fire dezincking of steel dust and sludge, characterized in that, The method includes the following steps: S1. The reducing carbon needs to be pretreated, the pretreatment step is to crush, screen and then acid soak the reducing carbon, filter and dry for standby; S2. Disperse the molasses and humic acid in water in turn, then add the pre-processed reducing carbon, fluxing agent, stabilizer and pore forming agent to form a slurry; S3. Granulate the slurry to obtain pellets; S4. Pore-forming the pellets to obtain the steel dust and sludge fire method zinc removal composite agent.

6. The preparation method of the composite agent for pyrometallurgical zinc removal from steel dust as described in claim 5, characterized in that, At least one of the following conditions a-d is met: a. The acid soaking is to soak the reducing carbon in 1-2mol / L hydrochloric acid for 2-4h; b. The granulation adopts extrusion granulation, and the pressure of the granulation is 5-10MPa; c. The discharge particle size of the granulation is 3-10mm; d. The pore-forming step is to preheat at 70-85℃ for 20-30min, then pass in saturated water vapor for 15-25min, cool down, and then dry to a water content of <5%.

7. A process for the application of a composite reagent for the fire dezincking of steel dust sludge, characterized in that, Sintering after adding the steel dust and sludge fire method zinc removal composite agent to the steel dust and sludge; The mass ratio of the steel dust and sludge to the steel dust and sludge fire method zinc removal composite agent is 100:10-30.

8. The application process of the steel dust and sludge pyrometallurgical dezincing composite reagent according to claim 7, characterized in that, The application process adopts a rotary kiln device, and the kiln section control is divided into a drying section, a preheating section, a high temperature section and a cooling section.

9. The application process of the steel dust and sludge pyrometallurgical dezincing composite reagent according to claim 8, characterized in that, At least one of the following conditions a-d is met: a. The drying section is heated at a temperature of 200-400℃ for 15-20min; b. The preheating section is heated at a temperature of 400-800℃ for 25-30min; c. The high-temperature section is heating at 800-1100℃ for 40-50 min d. The cooling section is cooling to 800-850℃.

10. The application process of the steel dust and sludge fire method dezincification composite reagent according to claims 7-9, characterized in that, The application process of the steel dust and sludge fire method dezincification composite agent has a dezincification efficiency of ≥97%, preferably 97.5-99%.

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